How many of you know what your star sign is? I’m betting it’s pretty much all of you, and I’m further willing to bet that a significant majority of you regularly check your horoscopes in some form or another. The problem is that astrologers are very good at what they do, and can make the vaguest of predictions sound like they’re tailored to you.
James “The Amazing” Randi is a renowned skeptic and the man who could reasonably be said to be personally responsible for the death of Uri Gellar’s career. He is also a super-awesome guy with facial hair that would make a Viking jealous. He did an experiment on a group of high schoolers to whom he was giving a speech. Before the speech, he obtained the names and birthdays of all the students who would be attending, and wrote them each individualized horoscopes (the kind about your personality in general) in sealed envelopes. He passed them out to the students at the speech and asked them to read them and rate their accuracy from 1 (least) to 5 (most). Half of the students rated their horoscopes a 5 and the rest were either a 3 or 4. There were no ones or twos. After taking that poll, he asked that each student pass their card to the person next to them, at which point the students realized that every horoscope was identical.
My point in telling you this story is that if the predictions are sufficiently amorphous, you’ll think it’s made for you because you’re stupid and gullible. That’s why you get sad when the paper tells you you’re only going to have a two-star day, and that’s why when you read this:
you assign meaning to it and see this:
Unfortunately for all you intellectually insecure mind-toddlers out there, astrology is all crap. All of it, without exception. It is, to quote Sheldon Cooper, “the mass cultural delusion that the sun’s apparent position relative to arbitrarily defined constellations at the time of your birth somehow affects your personality.” It is ass gravy of the highest order, and it has never been, nor will it ever be, remotely scientific in any way. So why do people believe it? Let’s take a look.
What Astrology (Thinks It) Is
There are approximately a bajillion (citation needed) different forms, schools, flavors if you will, of astrology, and some of them agree on some things, and some of them are inherently contradictory, but all of them agree on one fundamental principle: the stars and planets have some effect on individual human lives here on Earth. So let’s talk physics. How would they do that?
The first and most obvious choice is gravity. We all know that every single iota (I can use that word because I’m smart) of matter everywhere in the universe is pulling on every other iota of matter everywhere else in the universe, so it is undeniably true that Mars, for example, has a gravitational effect on you. We know that the moon and sun cause tides in the water, and we know that human beings are about 70% water, so it stands to reason that planets can affect us too, right, because we’re all connected and shit?
No. Wrong. The law of universal gravitation looks like this:

In that equation, F is the force felt by each mass, m1 and m2 are the two masses pulling on each other, G is the gravitational constant (equal to 6.67×10^-11 N m^2/kg^2), and r is the distance between the two masses in meters. If you know your algebra, you can see that an increase in distance will cause the force to plummet, to the point that the gravitational force that Mars exerts on you from a bajillion miles away (citation needed) is about an eighteenth of the force that your refrigerator exerts on you while you’re standing in front of it.

So it’s not gravity. That only leaves three fundamental forces of the universe, and we can rule out the strong and weak nuclear forces because they only work on a scale so tiny that your head would literally explode if you could actually grasp how tiny that scale is, which you can’t, so you’re safe for now.
That only leaves the electromagnetic force. That one’s easy to rule out, because human beings are magnetically and electrically neutral. Positive and negative charges attract each other so well that large objects like people and planets stay balanced. Any electrical imbalance will be quickly corrected when you zap the living shit out of your finger on the doorknob (static electricity).
This brings us to our first conclusion:
There is no known force responsible for the claimed principles of astronomy.
So now we’re left with what most astrologers actually claim: there is a different, unknown force—not one of those four—that acts on us. Let’s examine that impressively casual claim further. All the planets are given equal say in a horoscope, so we know that distance isn’t a factor (poor little has-been Pluto would be ignored like a reasonable person at a Tea Party rally), and neither is mass (Jupiter and the sun would dominate any and every horoscope, and they don’t). And now you have a problem.
If size doesn’t matter, then what about the asteroids? According to the best theoretical models, there are over a billion asteroids in our solar system bigger than 100m in diameter. 100m is small (about twice the size of the Epcot globe), but size doesn’t matter, so saddle up, astrologers, there’s work to do. Oh, and astronomers have discovered several hundred planets around other stars. Yes, they’re far away, but distance doesn’t matter either, so it would seem that astrologers have a hell of a lot of recalculation to do, the cocky fuckers. It is worth noting that no astrologer has been able to predict the location of extrasolar planets which, if they do indeed affect us, they should be able to, so that’s another strike for astrology.

And this brings us to our second conclusion:
There is no unknown force responsible for the claimed principles of astrology.
By now you may have picked up on the problem. If there’s no known force and no unknown force, there are no other options. There is literally nothing left. Some astrologers claim that it’s an immeasurable force, but I’ll just get that out of the way really quickly and say that if it has an effect on the real world, and it’s consistent (which it has to be to make predictions from it), it’s measurable. Logic is a cruel bitch, isn’t she?
But I (Think I) Know From (Misunderstood) Personal Experience That It Works!
No you don’t, you crashingly naive brain-infant of a person. Some of you are probably blowing me off even as you read, saying “Yeah, well this one time my horoscope said I’d find my true love, and then this one girl who was kinda cute smiled at me on the bus, so THERE.” Remember the Randi experiment I told you about. If you’re vague enough, you’ll get hits. Not only that, but people tend to remember the hits and forget the misses, so even if only one in ten horoscopes is right, you’ll remember them as having a better record than they do. That’s how ghost whisperers, cold readers, mentalists, and psychics work too, and some of them are so good at it that they can convince you that they’ve read your mind. They haven’t.
But What’s The Harm?
Ah, the oldest I-don’t-feel-like-arguing-anymore-because-you-make-me-feel-stupid-and-I-need-a-hug-and-also-a-popsicle response in the book. Most people, even if they don’t buy into a particular crackpot theory, are perfectly prepared to let it slide anyway. After all, who are they to tell other people what to believe?
The problem with all this shit is that it promotes irrational thinking. Skepticism should not be merely an occasional practice, it should be the central rule of your life. If someone tells you that cell phones cause cancer, doubt them. If someone tells you that the relative positions of the planets to arbitrarily assigned constellations at the time of your birth has a measurable and tangible effect on the future events of your life, punch them in the face. Every human being in the world should maintain an attitude of not accepting anything as true unless they have been given a good reason to, and “because the Bible tells me so” is not a good reason. Anecdotal experience is not a good reason. Personal experimentation is rarely a good reason. I must stress that this is not the same as closed-mindedness. I am open to anything, but if you come to me with an opinion, you had better make damn sure you can back it up. And it may sound arrogant, but yes, I’m saying everyone should think like me. But don’t take my word for it. Think for yourselves, for fuck’s sake.
A Parting Shot
Just as a quick little experiment, I decided to see what a typical Sagittarius is supposed to be like (me). Feast your brain-holes on this.
Sagittarians have a positive outlook on life, are full of enterprise, energy, versatility, adventurousness and eagerness to extend experience beyond the physically familiar. They enjoy travelling and exploration, the more so because their minds are constantly open to new dimensions of thought.
That’s pretty vague, but mostly positive and mostly accurate. I don’t know what dimensions of thought are, but I’m open to find out.
They are honorable, honest, trustworthy, truthful, generous and sincere, with a passion for justice.
Well I’m flattered. I don’t think of myself as especially generous, but the rest is right.
Sagittarians are usually modest and are often religious, with a strong sense of morality, though they tend to overemphasize the ethical codes they follow and worship beliefs about God rather than God Himself. This means that, negatively, they regard rigid, unloving, intolerant adherence to ritual and conventional codes as more important than the truths they symbolize or embody.
Aaaaaaaaand strike out. Not even remotely close even a little bit at all. Anyone who knows me in any capacity (reading the blog counts) knows that there is not a single clause in that paragraph that is correct. And so it goes.
Also, I’m supposed to be “cynically promiscuous.”
Ha.
Ha.
Ha.
Note: Virtually all of my knowledge on this matter comes from basic physics, logical reasoning, and Phil Plait’s Bad Astronomy page. Respect him enormously.
The Onion:
Sagittarius: You've always believed your work ethic and determination were what set you apart from the pack, but, as it turns out, it's that everyone else is a wolf.
Great post. I'm alledgely a “cancer” (which I always thought sounded needlessly pessimistic), and therefore moody and emotional. This is the EXACT opposite of my personality, but no matter how many true believers I explain this to, they always maintain their faith. Rediculous.
LOL, the personality characteristics you mention for Sagittarius can be found in anyone else who cares to cultivate such characteristics (in their behavior, thinking, and so on).
About “if the predictions are sufficiently amorphous, you’ll think it’s made for you”, that’s very true. Gullibility (sometimes stemming from desperation and wishful thinking) can cause a person to think they see “something” (such as something matching a horoscope prediction) where nothing exists. This can also be used to sell weight-loss stuff;-)
Anyway, very good article. Newspapers should replace their horoscope with this page.